Couldn't pass smog in CA P1135....

Well I just moved to Northern Cali and went to get my truck registered yesterday and it did not pass smog because their machine stated my CEL was on but it wasn't. The CEL lights up and blinks then shuts off like it should when I turn the key but I went to another friend and had them pull codes and diagnose it and I pulled a p1135 code bank 1 sensor one so I am pretty sure its the upstream o2 sensor. I guess I am wondering #1 why my CEL did not come on, also, if there is anything else that needs to be checked our before I take it back to get it smogged and waste more time/ money. Thanks for the input!

 

Some codes are considered 'pending' and don't turn on the CEL right away.

Assuming you have replaced that sensor, I'd get your friend to check for that code, and then CLEAR IT. Most hand-held scanners have that ability. If his can't, then purchase one that can.

I'd take it in the same day that code is cleared, before the ECU sets another 'pending' code.

 

Ok will do thanks!